Earthquake · reviewed by a seismologist
M 3.6mw
Earthquake near Hidden Valley Lake, CA
No earthquake was likely felt in Hidden Valley Lake in the 24 hours to 11:52 pm PST (07:52 UTC). The last one was M 2.6, 18 km (11 mi) W, at 4:44 pm PST on 8 November 2026, estimated intensity II (weak) in town. Every earthquake near Hidden Valley Lake
This page: a magnitude 3.6 earthquake was recorded 10 km (6 mi) east-southeast of Hidden Valley Lake, CA, at 7:16 am PDT on 23 August 2019 (14:16 UTC), 10 km deep. 77 people have reported feeling it to USGS.
USGS: 10km ESE of Hidden Valley Lake, CA
42 km (26 mi) NNE of Santa Rosa, CA · 110 km (69 mi) N of San Francisco, CA
- When
- 7:16 am PDT on 23 August 2019 ()
- Where
- 10 km (6 mi) east-southeast of Hidden Valley Lake, CA · earthquakes near Hidden Valley Lake
- Magnitude
- M 3.6 (mw)
- Depth
- 10 km below the surface
- Felt
- 77 reports · strongest reported intensity III
- Measured shaking
- intensity V (ShakeMap)
- Nearest
- Napa County, 31 km SSE
- Nearest mapped fault
- Hunting Creek-Berryessa fault system, 5 km from its surface trace — near is not the same as on
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2560 days ago
Earthquake alerts for Hidden Valley Lake, CA
Get a notification in this browser when USGS records an earthquake near Hidden Valley Lake, CA. No account or email needed.
Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.
At this magnitude and depth, people at rest would likely notice it out to about 69 km (43 mi) from the epicentre. In Hidden Valley Lake, 10 km away, the estimate is intensity III (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.
Likely felt in: Angwin 22 km, intensity III · Cobb 24 km, intensity III · Calistoga 24 km, intensity III · Clearlake 26 km, intensity III · Windsor 40 km, intensity II · Healdsburg 40 km, intensity II · Kenwood 41 km, intensity II · Santa Rosa 43 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 3.8 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.6 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 45,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 2,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,400× the energy of this one
- This earthquake M 3.6 about 3.8 tons of TNT
- Around the size people start to feel M 3.0 this one released 7.9× more
Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.
For this area
The largest earthquake within 50 km since 2016 was M 5.0 on 2016-12-14 — about 130 times the energy of this one.
Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.
Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.
Where
Epicentre 38.7718, -122.4518. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Napa County, CA | 31 km (20 mi) | SSE | earthquakes near Napa County |
| Lake County, CA | 45 km (28 mi) | NW | earthquakes near Lake County |
| Yolo County, CA | 49 km (30 mi) | ESE | earthquakes near Yolo County |
| Colusa County, CA | 49 km (30 mi) | NNE | earthquakes near Colusa County |
| Sonoma County, CA | 49 km (31 mi) | WSW | earthquakes near Sonoma County |
| Sutter County, CA | 71 km (44 mi) | ENE | earthquakes near Sutter County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
59 earthquakes have been recorded within 50 km since this one.
- 2.8 9km WNW of Cobb, CA
- 2.0 7km NW of The Geysers, CA
- 1.5 6km WNW of The Geysers, CA
- 1.6 3km NW of The Geysers, CA
- 1.6 7km NW of The Geysers, CA
- 1.9 10km NW of Cobb, CA
- 1.7 7km NW of The Geysers, CA
- 2.0 6km NW of The Geysers, CA
- 1.5 7km NW of The Geysers, CA
- 1.7 4km W of Cobb, CA
- 1.5 4km NW of The Geysers, CA
- 1.6 7km W of Cobb, CA
- 1.6 12km ESE of Hidden Valley Lake, CA
- 2.8 2km N of The Geysers, CA
- 2.5 4km NW of The Geysers, CA
Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.
On USGS
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.